Optimizing the design of trefoil phase plates for wavefront coding

Wavefront Coding (WFC) is a technique which makes use of generalized aspheric optics and digital signal processing to greatly increase the depth of focus and/or reduce the cost of imaging systems. Usually, cubic phase elements are employed to obtain images that are insensitive to defocus and some aberrations. In this work we will show how to optimize the design of a trefoil phase plate in order to optimize its performance for large amounts of defocus.